Colored roofing granule



'. Patented June v1,939v I Illirizu'r 'OFFICE alessiaI conoaan aoome caANULa Henry B.Gundlach, Baltimore, Md., assigner to Central Commercial Company, a-corporation l Application July l, 1936, Serial No. 88,410

This invention relates to roong and more particularly to colored granules therefor and the method of coloring the granules.

One of the objects of the invention is the provision of new and improved means for attaching or securing color pigment to the `surface of 'gran-v ules used on rooiingv material and the, like.

Another object of the invention is` the provision of new and improved means for color coat- 19 ing granules for use on roong and the like, that is insoluble and when applied to the rooilng material will resist, to a marked degree, the deleterious action of the weather including the actinic rays of the 's'un and will remain -fixed on the roof- 5 ing for an indefinite length of time.'

A still further object of the invention is the provision of a new and improved method for retaining color pigment on granulesand at the vsame timef providing a more or less roughened 20 surface on the exterior of the colored granule whereby the granule may be easily retained on the roofing material by the weatherproof binder conventionally employed.

A f urther'object of the invention is the provision of a new and improved colored granule that may be prepared at a minimum of expense; that will be firmly and permanently retained in position onthe roong material; that is insoluble;v and, one in which the color isuniform and will remain fresh in appearance for an indefinite lengthof time. 4 j I Other and further objects and advantages of the v.invention will appear from the following de- `scription taken in connectionwith the accompanying drawing, in which:

, Fig. 1 isa cross section' of a roofing strip showing the granules in position thereon; and

Fig. 2 is a cross section, on an enlarged scale,

of one of the granules.

It is common practice to articially color granules4 for use on rooiing material and the like; but, owing to the continued exposure of this material to all kinds-of weather conditions, including the y 'actinic rays lofthesun, the colormay fade and the retaining material may be caused to chip oil -or gradually dissolve, it not insoluble, or the binder for holding the granules to the rooilng yfelt may be so adversely.V aifected by the suns rays or the binder dissolve to such an extent that 1 and more especially if the granule itself is also transparent since the actinic rays of the sun will be transmitted through the granule thereby effecting photo-chemical changes in the asphalt and causing the same to deteriorate. In the use 5 of certain binders that are more or less soluble, even though the solubility be fairly low, the exterior or exposed surfaces of the binder will, in time, dissolve to such an extent that the granules will become loose and later detached.

" The present invention seeks to remedy these difficulties by the provision of \a granuie having color pigment secured to its exterior by a composition that is insoluble and that will not transmit the deleterious light rays to roofing material 15 and to the binder employed for attaching the color pigment to the granules.

' Referring now to the drawing, the reference character I0 designates a foundation roofing felt which has been impregnated with a -bituminous 20 or other wateryor weatherproof material as is usual in such constructions. The felt I0 is covered on one side by a binder of bituminous composition II of a rather high melting point, as asphalt or other'suitable bituminous material. 25 Granules I2, having color pigment I3 secured to the surface thereof, are embedded in this material for protecting the felt. 'Ihe granules may be of any suitable material, such as greenstone, trap rock, slate, quartz, or the like.

Inthe preparation ofl the granules, the material isA first ground and then screened to the proper size in the usual or any suitable manner.

` After screening or sizing, the granules are given a coat il of a mixture, the base of which is a 35 soluble silicate such as sodium silicate: Sodium silicate alone may be employed, with or without color pigment, but if so, the sodium silicate is preferably fused onto the granules.v Preferably, however, the sodium silicate is applied Awith or 40 without the color pigment together with a hardener or insolubilizer suchy as clay, calcium hydroxide, zinc oxide, or the like. This coat is apt plied in the conventional manner.

while .this mst coat is being appnes, which 45' may be done in a rotary kiln by pouring a mixture of sodium-silicate, water, and an insolubilizer or a solution of the sodium silicate alone, as the case may be, into the mass of granules and heating the 60 mass for drying the same,.the granules are continually agitated to prevent agglomeration. After the first coat has been applied by drying the same on the surface of the granules by application of heat or by subjecting the coat to sufiicient heat to second coat i5 is applied.

The amount of sodium silicate of the rst coat may vary within rather wide limits and the subsequent treatment may vary considerably. It is immaterial how the coat is applied or what -type or amount of sodium silicate is employed.

The following formulas for the rst coat will Y indicate the proportions of the ingredients and are given by way of example only:

Fms'r Com Formula No. 1

Pounds Lawrence clay 25-40IA Pigment 0-10 Sodium silicate 20-40}B Water 10-22 Mix A and B togetherand apply to one ton granules, dry in carbon dioxide free air and heat to 600-l100 F. for 10-30 minutes, in order that clay and silicate react.

Formula No. 2

. Pounds Calcium hydroxide 20-25 Zinc oxide 4- 6 Pigment- 0-10 Sodium silicate 50-'10 Water 20-30 Dry as in above first coat and heat to 400- 600. F. for 10-30 minutes. If desired, the sodium silicate may be first applied and dried and the insolubilizing composition applied to the heated granules.

After the first coat has been applied and has4 been dried on the granule, a second coat is now applied which is opaque and will form a more or less rough surface on the exterior of the granule.

This second coat is a reaction product of phosphoric acid on a silicate or on calcareous, aluminous or siliceous material, or on any two of these materials. 'I'he reaction products of phosphoric acid andcompounds of one or more of the common metals of Groups III, IV, VII or VIII of the periodic classification of the elements that are capable for forming sesqui-oxides may also be employed. The compounds of these elements most suitable are the oxides, hydroxides or carbonates thereof. The compounds of the more common metals of Group II of the periodic classification of the elements as the oxides, hydroxides or carbonates may also be used with satisfactory results. Satisfactory results are obtained by calcining a mixture of clay, lime and siliceous material, or any two of these materials, grinding the calcined material and then mixing the groundV material with the granules and color pigment and adding phosphoric acid.

vThe c following formulas are given by way of lexample only, as compositions or mixtures that may be sintered or calcined and reduced to form what may be termed cement powder for reacting with phosphoric acid to form a binder for atl 2,1ea,e7s`

fuse the sodium silicate, as the case may be, the

'Formula No. 3 i "Per cent Calcium carbonate 48.0 Aluminum oxide 52.0

Formula No. 4 Per cent' Sodium silico-uoride 36.4 t Calcium uoride 5.1 Aluminum oxide 32.4 Silica 26.1

` Formula No.` 5

` Per cent Calcium carbonate 16 to 17 China clay 83 to 84 SEcoNn COAT After the granules have been treated with the rst coat including the insolubilizing composition, the second coat is then applied.

The following formulas have been found to give satisfactory results ,for the second coat. 'I'hese vformulas are given .by way of example only:

' Formula No. 1

Pounds Cement powder 12 Pigment 4-25 Filler, if desired, possibly as'much as 15 lbs-silica. A

The first coat is soluble to a certain extent but -whn covered by the second coat containing insoluble phosphate, there appears to be a. reaction between the elements of the two coats. At any rate, the resultant material-is more nearly insoluble than the material of either coat alone. This is considered an important feature of the invention. This method of coating the granules also reduces the tendency to bloom or eilioresce. The color too appears to be more vivid, which is probably due to a. better distribution of color. Furthermore, the second coat being opaque will prevent the passage of actinic rays therethrough and being more or less rough on its surface, the bituminous binder will firmly anchor the granuie to the roofing material.

It is also common practice to employ frits or other igneous binders for attaching color pigment to the surface of the'granules. Frit is applied in a single or a plurality of coats and the color pigment may be in either orboth coats. In any event, the exterior of the colored granule will be smooth and glassy and consequently, the granules will not be sufllciently iirmly held by the bituminous binder oi' the roofing material to prevent their becoming loosened by themechanical action of hail, rain, wind, andthe like. Furthermore, since the fr it ismore or less transparent, and if used on transparent or translucent granules, the suns rays will pass through the same and injuriously effect the adjacentl adhering binder, whereby the granules will loosen and become displaced.

2,168,678 This difliculty lis overcome by applying an applied in the same manner described before and -the color pigment may be in the outer or phosphate coat or in both or all coats, as desired.- The rough surface of the phosphate coat will constitute means for anchoring the granule to the roong material inasmuch as the-asphaltic or bituminous binder will more rmly adhere to a rough surface than to a smooth one.

Instead of employing an outen coat composed of the reaction product of phosphoric acid, any composition or mixture that will form a cementitious waterproof cement or binder and thatls more or less opaque and has rough exterior may also be employed.

It is thought from the foregoing taken in oo nnection with the accompanying drawing that the method and process of my invention will be apparent to those skilled in the art, and that' -and an insolubilizer, drying the 'same on the granule and'then applying a cementitious substantially insoluble material on said rst coat,

said material including phosphoric acid as the major ingredient asidefrom water and color pigment to the surface of-'the coated granule, and' then drying thepsecond coat.

, 2. A method of coloring roofing granules which comprises coating the granule with a soluble silicate and a hydroxide of the calcium group, dehydrating the silicate, and then covering the coated granule with a second'coat comprising an insoluble phosphate having color pigment incorporated therein, the phosphate constitutiing the 'principal ingredient of the coating.

3-. Composition 'roofing comprising, asheet ofv roofing material impregnated with a bituminous compound and having coloredgranules secured -eral matter having an inner coat of sodiumv sili- Y cate and an outer coat comprising color pigment secured to the surface of said inner coat by the reaction product of a silicate' and a radical of phosphoric acid as. the major ingredient by weight, aside from-the water, 5. The method of coloring granules whic u comprisesfusing an igneous coatV including a soluble silicate on the surface ofthe granule and then securing color pigment to the surface of the coated granuler by a cement'formed by the reaction product loi.' calcined calcareous, aluminous and siliceous materials ahd phosphoric acid.

8. The method of coloring granules which comprises coating the granule with sodium silicate f and an insolubilizing agent, drying the mass, and then-coating the granule with a second coat comprising color pigment, a composition including a phoric acid.

compound of one of the common metals of Groups III, IV, VII or VIII ofthe periodic cla'ssiication of the elements capable of forming a sesqui-oxide and phosphoric acid.

'1. A method of coloring granules for use on composition roofing which comprises covering the granules with a coat formed from a mixture of s. Pounds Lawrence clay 1 25-40 Color pigment 0-,10 Sodium,silicate 20-40 Water 10-22 for each ton of granules, drying the mass in carbon dioxide free air and heating from 600 F; to 1100 F. and then coat the granules with a mixture comprising a color pigment and an insoluble phosphate.

8. A method of coloring granules for use on composition roong which comprises covering the granules with a coat formed from a mixture of Pounds Calcium hydroxide 20-'25 Zinc oxide L-- 4-6 Pigment 0-10 Sodium silicate g 50-70 Water- 20-30 dry the mass and heat from 400 F. to 600 F. foro from 10 t'o 30 minutes and then applying a coat of an insoluble phosphate.

9. A method lof coloring' granules' for use on compositionroong which comprises coating the granules with a composition including sodium silicate, -drying the same at a temperature between 600 F. and 1100 F. and then applying a coat containing a phosphate as the reaction product of phosphoric acid on sintered silicates and color pigment and nally 'drying the mass at a temperature between 400 .to 600 degrees Fahrenheit.

10. A method of coloring granules which comprises coating the granules with the reaction 1 product of a soluble silicate and an insolubilizer, drying the mass, and then applying a coat comprising color pigment and a cementl formed b y the -reaction product of va calcined .mixture of ground siliceous, aluminous material and phos- 11. A methodof coloring granules for *use on composition roong which comprises covering the granules with a coat formed from a mixture of: ,Y Pounds Lawrence clay 25-40 Color pigment 0-10 Sodium silicate 20-40I Water l 10-22 foreach ton ofgranules, drying the mass in car-y bondioxide f ree air and heating from'600" F. to 1100 F. and then applying a second coat formed from a mixture of:

and water, to form a cement, saidliezement'powder. comprising calcined mixture of ground clay and siliceous material. i

'HENRY R.GUnDLAcH.- 

